(a) Field of Disclosure
The present disclosure of invention relates to a display device and a driving method thereof, and more particularly, to a display device capable of reducing power consumption and a driving method thereof.
(b) Description of Related Technology
A display device is often required for use as part of a computer monitor, a television set, a mobile phone and like image displaying devices which are widely used. The display device may include a cathode ray tube (CRT), a liquid crystal display (LCD), a plasma display, or the like.
The display device typically also includes a graphic processing unit (GPU) and a signal controller as well as the image display panel itself. Typically, the graphic processing unit (GPU) transmits an image data signal representing consecutive screens' worth of to-be-displayed imagery to the signal controller and the signal controller then responsively generates control signals for each of the consecutive screens (frames) for use in driving the display panel. The signal controller typically transmits the control signals together with the respective image data signals to the display panel to thereby timely drive the display device.
The imagery which can be displayed on the display panel may be classified as being either a still image or a motion picture image. The display panel generally displays several frames within each second. In this case, when the image data included in each of plural frames are the same as each other, a still image is displayed. On the other hand, when the image data included in each frame are different from each other, the motion picture may be thereby formed and displayed.
In a case where both a motion picture and a still image are to be displayed on the same display panel, even though the still image is a nonchanging one, the signal controller nonetheless typically has transmitted to it and it receives the same image data over and over again from the graphic processing unit (GPU) for each of many frames. Retransmission of the image data, even if it is the same data, consumes power and thus there is a problem in that power is unnecessarily consumed when a same image is to be displayed over and over again.
Recently, research for reducing the power consumption of display devices has been attempted. As one of several proposals, a method is suggested in which the image data of the still image is stored in a local frame memory of the signal controller by adding such a still image retaining frame memory into the signal controller and the so-stored image data is then provided to the display panel while displaying the still image rather than re-transmitting the same data and reprocessing it over and over. This is called a Pixel Self Refresh (PSR) mode. Since the image data does not need to be transmitted from the graphic processing unit (GPU) while displaying the still image, the graphic processing unit may be at least partially inactivated during this time, and as such, its power consumption may be reduced.
However, even in the case where the signal controller is driven in the PSR mode where the still image retaining frame memory has been added, there is an apparently unrecognized problem that power consumption is still unnecessarily large.
The above information disclosed in this Background of the Technology section is only for enhancement of understanding of the here disclosed inventive subject matter and therefore it may contain information that does not form part of the prior art as already known to persons of ordinary skill in the pertinent art.